/*
 * $Header: /home/cvs/jakarta-tomcat/src/share/org/apache/jasper/compiler/BeanRepository.java,v 1.4 2004/02/23 06:22:36 billbarker Exp $
 * $Revision: 1.4 $
 * $Date: 2004/02/23 06:22:36 $
 *
 *
 *  Copyright 1999-2004 The Apache Software Foundation
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

package org.apache.jasper.compiler;


import java.beans.Beans;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Vector;

import org.apache.jasper.JasperException;

/**
 * Holds instances of {session, application, page}-scoped beans 
 *
 * @author Mandar Raje
 */
public class BeanRepository {

    Vector sessionBeans;
    Vector pageBeans;
    Vector appBeans;
    Vector requestBeans;
    Hashtable beanTypes;
    ClassLoader loader;
    
    public BeanRepository (ClassLoader loader) {
	sessionBeans = new Vector(11);
	pageBeans    = new Vector(11);
	appBeans = new Vector(11);
	requestBeans    = new Vector(11);
	beanTypes    = new Hashtable ();
	this.loader = loader;
    }
    
    public boolean checkSessionBean (String s) {
	return sessionBeans.contains (s);
    }
    
    public void addSessionBean (String s, String type) throws JasperException {
	sessionBeans.addElement (s);
	putBeanType (s, type);
    }
    
    public boolean hasSessionBeans () {
	return !sessionBeans.isEmpty ();
    }
    
    public Enumeration getSessionBeans () {
	return sessionBeans.elements ();
    }
    
    public boolean checkApplicationBean (String s) {
	return appBeans.contains (s);
    }
    
    public void addApplicationBean (String s, String type) throws JasperException 
    {
	appBeans.addElement (s);
	putBeanType (s, type);
    }
    
    public boolean hasApplicationBeans () {
	return !appBeans.isEmpty ();
    }
    
    public Enumeration getApplicationBeans () {
	return appBeans.elements ();
    }
    
    public boolean checkRequestBean (String s) {
	return requestBeans.contains (s);
    }
    
    public void addRequestBean (String s, String type) throws JasperException {
	requestBeans.addElement (s);
	putBeanType (s, type);
    }
    
    public boolean hasRequestBeans () {
	return !requestBeans.isEmpty ();
    }
    
    public Enumeration getRequestBeans () {
	return requestBeans.elements ();
    }
    
    public boolean checkPageBean (String s) {
	return pageBeans.contains (s);
    }
    
    public void addPageBean (String s, String type) throws JasperException {
	pageBeans.addElement (s);
	putBeanType (s, type);
    }
    
    public boolean hasPageBeans () {
	return !pageBeans.isEmpty ();
    }
    
    public Enumeration getPageBeans () {
	return pageBeans.elements ();
    }

    public boolean ClassFound (String clsname)
    throws ClassNotFoundException {
	Class cls = null;
	//try {
	    cls = loader.loadClass(clsname) ;
	    //} catch (ClassNotFoundException ex) {
	    //return false;
	    //}
	return !(cls == null);	
    }
    
    public Class getBeanType (String bean) throws JasperException {
	Class cls = null;
	try {
	    cls = loader.loadClass((String)beanTypes.get(bean)) ;
	} catch (ClassNotFoundException ex) {
	    throw new JasperException (ex);
	}
	return cls;
    }
  
    public void putBeanType (String bean, String type) throws JasperException {
	try {
	    beanTypes.put (bean, type);
	} catch (Exception ex) {
	    throw new JasperException (ex);
	}
    }
    
    //public void putBeanType (String bean, Class type) {
    //beanTypes.put (bean, type);
    //}
    
    public void removeBeanType (String bean) {
	beanTypes.remove (bean);
    }
    
    // Not sure if this is the correct way.
    // After pageContext is finalised this will change.
    public boolean checkVariable (String bean) {
	return (checkPageBean(bean) || checkSessionBean(bean) ||
		checkRequestBean(bean) || checkApplicationBean(bean));
    }

    // Ideally this method should belong to the utils.
    public Class getClass (String clsname)
	throws ClassNotFoundException {
	    Class cls = null;
	    if (clsname != null) {
		cls =  loader.loadClass (clsname);
	    }
	    return cls;
    }

    public boolean beanFound (String beanName)
	throws ClassNotFoundException {
	    try {
		Beans.instantiate (loader, beanName);
		return true;
	    } catch (java.io.IOException ex) {
		// Ignore it for the time being.
		return false;
	    }
    }
}